Question: What is the birth date of writer Principia Mathematica?
Paraphrase: What is the birth date of author Principia Mathematica?
SPARQL (Wikidata): SELECT ?answer WHERE { wd:Q163335 wdt:P50 ?X . ?X wdt:P569 ?answer}
Answer: 1872-05-18T00:00:00Z, 1861-02-15T00:00:00Z